This invention relates to personal mobility vehicles, and particularly to a self-propelled scooter which is easily assembled and disassembled.
Personal mobility vehicles have reached widespread acceptance for use by persons with partial and total walking disabilities. Personal mobility vehicles are generally more rugged, and employ wider tires, than wheelchairs so they may be maneuvered over terrain not generally accessible by wheelchairs. Personal mobility vehicles are self-propelled and generally have the appearance of a downsized golf cart.
In use, most personal mobility vehicles are capable of being disassembled for storage and/or transportation, such as in the trunk of an automobile. Consequently, it is important that each of the several units comprising the disassembled vehicle be as lightweight as possible, not exceeding about fifty pounds. Further, assembly and disassembly of the vehicle should be reasonably simple so that users can disassemble and reassemble the vehicle in a few minutes without complicated procedures. Thus the connection mechanism for connecting frame portions of the vehicle should be simple to operate to both assemble and disassemble the vehicle, should provide a positive connection which cannot be compromised by the user, and should be able to withstand forces imposed by the weight of the rider and stresses during assembly and disassembly. Therefore, in addition to the rugged design such vehicles should be of relatively simple design.
Unfortunately, personal mobility vehicles have not fully met the foregoing goals. Particularly, the connection mechanisms for connecting the front and rear frame units of prior personal mobility vehicles have required a sophisticated level of manual dexterity to operate. For example, the front and rear frame units of many prior vehicles are assembled by slidably attaching mating rods or frame portions on opposite sides of the respective front and rear units, and attaching the rods or frame portions with pins. Examples of such devices can be found in the Kinghorn U.S. Pat. No. 3,249,171, and Kramer U.S. Pat. No. 4,570,739. While such vehicles may be readily dismantled by removing the pins and withdrawing one set of tubes from the other, more than casual dexterity is required to align the separate rods or frame portions on the two sides of the vehicle during assembly, often while the mating frame portions are held in an elevated position by the user. Also, it is not an easy chore to align the pin holes on the mating frame portions for insertion of the safety pin. If the user becomes frustrated by the safety pin and omits its reinsertion, the vehicle could become inadvertently disassembled during use, leading to a highly dangerous condition. Further, the weights of the vehicle and rider cause a bending stress at the junction of the mating tubes, thereby weakening the connection mechanism and causing eventual misalignment, thereby increasing the difficulty of assembly and necessitating costly repair and correction.
Others have suggested a hinge and hinge pin arrangement to fasten the frames together, together with a support strut to brace the frame. However, such arrangements are subject to the same difficulties as the Kinghorn and Kramer structures, with the additional difficulty that a substantial amount of stress is imposed on the pin itself. Arpin U.S. Pat. No. 3,388,761 discloses an example of this latter arrangement. Mowat et al. U.S. Pat. No. 4,452,327 overcomes many of the alignment problems associated with the Kinghorn, Kramer and Arpin arrangements by employing a hook and bar assembly, but the Mowat et al. arrangement creates an undesirable sheer stress on the connection mechanism.
Braume U.S. Pat. No. 4,037,678 overcomes many of the structural difficulties of other vehicles by employing a J-hook flange and lip mechanism arranged so that portions of the frame bear in compression against each other. However, Braume requires bolts and nuts to hold the assembly together, so the vehicle is not easily assembled and disassembled.
The present invention overcomes the difficulties of the prior art by providing a connector mechanism which operates in compression to support the weight of the vehicle and rider, provides a positive connection whose safety cannot be compromised, and is quickly and easily assembled and disassembled.